The present invention relates to an optimal control method and apparatus for an elevator system having a plurality of elevator cars and, more particularly, to an optimal elevator control method and apparatus for controlling the elevator cars effectively.
In general, an optimal elevator control system for controlling a plurality of elevator cars is designed to realize effective travel of the elevator cars and thereby to provide improved transportation service in a building in which such elevator cars are located. For this purpose, when a hall call has been made by the passenger at a certain hall in the building, the control system performs a call allocation in which one elevator car is allocated in response to the hall call so that the most effective service would be attained in the building.
However, the call allocation itself is unable to make a precise prediction of the future hall calls to be made by the passengers. The call allocation has been designed to increase the transportation capacity in combination with a traffic control rule preferably used for a traffic-flow control system. The control process in which a suitable traffic control rule is determined according to the current traffic-flow for the control of the elevator cars is referred to as xe2x80x9cpattern operationxe2x80x9d hereinafter.
According to the pattern operation, during morning rush hours in which heavy traffic occurs, service halls where the elevator service is available for the passengers are divided into several zones. Also, one or more elevator cars are allocated to the hall or halls grouped in one zone. The passenger waiting at the main hall is allocated to the zone including the hall where the passenger intends to go. Indeed, this operation (referred to as xe2x80x9czoning operationxe2x80x9d or xe2x80x9cgrouping operationxe2x80x9d) can increase the efficiency of the transportation. One example of the zoning operation is disclosed in the Japanese Patent Unexamined Laid-Open Publication No. 2-43188.
The conventional operations designed to divide the halls into several zones or groups are effective to control a relatively simple traffic-flow which would occur in the morning rush-hour. However, such operations are less effective for other complicated traffic-flows. Also, among others, only the zoning operation is useful for the specific type of traffic and its analogues. Further, in order to control a variety of traffic patterns, an independent zoning or allocation rule should be heuristically generated for each of the traffic patterns. However, the automatic generation of such rules can considerably be difficult.
To overcome these problems, in a method and system for an optimal control of a group of elevator cars according to the present invention, a transportation work assigned to each elevator car comprises at least one work unit (referred to as xe2x80x9cmission unitxe2x80x9d hereinafter) of a transportation from one departure (origin) floor to another destination floor. The mission units are assigned to a plurality of work groups (referred to as xe2x80x9cmission groupsxe2x80x9d hereinafter). Then, the mission groups are dynamically allocated to the elevator cars. This allows to increase a transportation ability and efficiency for various traffic flows. Also, this allows to provide a general zoning operation. Further, an automatic generation of work rules, i.e., mission groups, capable of increasing the transportation ability and efficiency can be done in the combination of an optimal technique.